Quantifying Cooperative Binding of Cholera Toxin B with Gangliosides

Abstract

Many biochemical processes involve binding between carbohydrates and biomolecules on the surface of cells. These may involve multivalent interactions that can considerably alter the binding specificity and avidity of biomolecules. A novel nanocube sensor has been developed to elucidate the cooperativity in binding of biomolecules to carbohydrates. A fluidic supported lipid bilayer coated on the nanocube sensor allows this system to mimic a cell membrane in vitro. Cholera toxin B (CTB) subunit has been taken as a model system and its binding with several gangliosides has been demonstrated using this sensor. The amount of CTB bound to the lipid bilayer is then quantified by observing the shifts in the quadrupolar localized surface plasmon resonance peak using a standard laboratory spectrometer.

The ultimate objective of this research is to provide a diagnostic tool to quickly identify diseases. This inexpensive, label free, high throughput technology allows the testing of several conditions simultaneously. This helps researchers understand the mechanism of binding and quantify the binding of biomolecules, which may enable the development of treatments for diseases involving membrane recruitment.